1. Field of the Invention
This invention relates generally to an apparatus and a method for extracorporeal blood treatment. More particularly, the invention provides an apparatus for treating certain diseases by way of an extracorporeal circuit capable of simultaneously and/or intermittently carrying out three separate modes of treatment.
2. Description of the Prior Art
The exact mode of infection with the Human Immunodeficiency Virus (HIV) is not clear. The commonest method of transmission is contact with body fluid especially blood products. The clinical stages of HIV infection can be divided into the exposure phase, acute phase, asymptomatic phase, and finally the Acquired Immune Deficiency Syndrome (AIDS) phase. In the acute stage (after exposure), the patient develops symptoms suggestive of influenza, i.e., congested nasal sinuses, headaches, generalized muscle pain, back pain, and low grade fever. These symptoms last for a few days or weeks. During this phase the blood will contain a high concentration of HIV viruses. In the asymptomatic phase, the patient will have no symptoms, however the macrophages, lyphocytes as well as the glial cells are attacked continuously by HIV viruses. This phase may last for months or years. The final stage is AIDS, where the patient loses his immune system and becomes susceptible to intractable infections that will eventually terminate his life.
HIV virus consists of double strand of ribonucleic acid together with a DNA polymerase enzyme called reverse transcriptase which transcribes single stranded viral RNA into numerous copies of double stranded DNA when entering the susceptible cell. The viral DNA enters the host cell nucleus and some of which will be integrated into the cell chromosomal DNA. This is called a provirus. This coincides with the acute phase of infection. This HIV pro-viral transcription can also be switched by other viruses such as Herpes Simplex Type I, Cytomegalovirus, Varicella Zoster Virus, and Hepatitis Virus. When the proper signals are received by the viral DNA, copies of the viral RNA proceeds. In the cytoplasm, the viral mRNA (messenger RNA) are translated into viral protein. A new virion will bud from the cell surface together with a piece of plasma membrane forming the envelop of the virus. Millions of virion are manipulated by the HIV and leads to a complete collapse of the immune system. This is the stage that the patient has the Acquired Immune Deficiency Syndrome, i.e., AIDS. The patients become susceptible to minor infection which will bring their demise.
Prior art devices are known for carrying out extracorporeal treatment of the blood. Many extracorporeal treatment methods have become well established as routine methods of treating specific conditions or diseases. Examples of extracorporeal treatment methods of known effectiveness include those adapted for extracorporeal blood oxygenation, plasmapheresis, radiotherapy, and extracorporeal treatment by pharmacological and chemotherapeutic agents.
Specific examples of extracorporeal blood treatment devices and methods are described in the following:
U.S. Pat. No. 4,692,138 issued to Troutnet, et al. discloses a pump block which is used to interface an irradiation chamber with a roller pump. Such a pump block is incorporated into an extracorporeal apparatus wherein photoactivatable agents are added to the patient's blood prior to extracorporeal irradiation of the blood. After such irradiation is completed, the blood is returned to the patient.
U.S. Pat. No. 4,321,918 to Clark, discloses a process and method of extracorporeal irradiating whole blood to alter lymphocyte function.
U.S. Pat. No. 4,576,143 issued to Clark discloses a process and method of extracorporeal irradiating whole blood for the purpose of modifying the immune response in humans affected with immune disorders.
U.S. Pat. No. 4,683,689 to Edelson teaches a method and system for externally treating the blood of a cancer patient with UV radiation for reducing undesirable cell population. A photoactive chemical agent having an affinity for nucleic acid cells intermolecular attractive forces draw the agent into an intercalated relationship with the nucleic acids of the lymphocytes. Prior to activation, the agent has little or no effect on the cell chemistry. However, upon irradiation the agent forms certain covalent attachments or otherwise complexes with nucleic acids of the cell. Thereby inactivating the nucleic acid chains and inhibiting the metabolic functions of the cell. In this manner, the cell's processes, having been disrupted, and in particular its ability to divide prevented, inactivation or death of the cell results.
None of these extracorporeal irradiation methods and devices of the prior art have been specifically designed for the treatment of blood infected with HIV. The T-lymphocytes which contain or have been infected by the HIV virus may become structurally fragile. This suggests that such cells may be selectively disrupted or destroyed. Furthermore, these extracorporeal blood treatments are conducted on whole blood, none of the references disclose, teach, or suggest, separating whole blood into its components and separately treating each blood component under the most effective treatment conditions, reconstituting the blood component and returning the reconstituted blood to the patient.
U.S. Pat. Nos. 5,074,838 and 5,104,373 relate the extracorporeal devices for the treatment of blood infected with the HIV virus at elevated blood temperatures.
U.S. Pat. No. 5,074,838 to Kroyer describes an extracorporeal thermo-therapy device to raise the blood temperature around two degrees centigrade above normal body temperatures to destroy or attenuate HIV viruses and cancer cells.
U.S. Pat. No. 5,104,373 to Davidner et al., discloses an extracorporeal apparatus and method for treating certain blood borne infections including infections with HIV virus by three treatment modalities which can be conducted simultaneously or separately. The first modality comprises a means for hyperthermically treating the blood at a reduced pH under variable flow conditions. The second modality involves a means for mechanically shearing blood cells which disrupts the infected cells and/or separates viral particles from the host cells or potential host cells. The third modality involves means for subjecting whole blood or the mononuclear leukocyte component to irradiation frequencies selected from X-ray, ultraviolet, infrared, visible, laser or radio frequencies prior to recombing the treated cells with the remaining blood plasma and/or other formed elements.
The apparatus and method of the present invention differs from the apparatus and methods referred to above in the prior art patents. This difference provides for a treatment of viruses and other unwanted cells by fractionating the blood into components which can be separately treated with high energy electromagnetic radiation allowing for optimum processing conditions for each fraction.